The Science of Mentos and Diet Coke

The startling reaction between Diet Coke and Mentos sweets, made famous in thousands of YouTube videos, finally has a scientific explanation.

If you drop a pack of Mentos into a bottle of Diet Coke, you get this huge fountain of spray and Diet Coke foam coming out,” says Tonya Coffey, a physicist at Appalachian State University in Boone, North Carolina. “This was a good project for my students to study because there was still some mystery to it.”

Experiments in a 2006 edition of the Discovery Channel programme Mythbusters suggested the chemicals responsible for the reaction are gum arabic and gelatine in the sweets, and caffeine, potassium benzoate and aspartame in the Coke. But there have been no rigorous scientific studies of the reaction until now…

I'm Robert Simpson and I work at Google in London. I am the creator of <a href="http://dotastronomy.com">.Astronomy</a>. I am astrophysicist formerly of the <a href="http://zooniverse.org">Zooniverse</a> at the University of Oxford.